package cn.liontalk.concurrent.shuati;

import java.util.Scanner;

public class LiFangGeng {

    public static void main(String args[]) {
        Scanner sc = new Scanner(System.in);
        while (sc.hasNext()) {
            double a = sc.nextInt();
            double start = 0;
            double end = 0;
            double mid = (start + end) / 2;
            while (mid * mid * mid - a > 0.0001) {
                if (mid * mid * mid > a) {
                    end = mid;
                    mid = (start+end)/2;
                }else{
                    start = mid;
                    mid = (start+end)/2;
                }
            }
            System.out.println(mid);
        }
    }
}
